Stephen Trentalange STAR Upgrade Workshop June 11, 2012 FMS Status/Plan Stephen Trentalange STAR Upgrade Workshop June 11, 2012

Improvements for Run 11 Repair of small cells Change of HV profile to approx uniform acceptance in pT Change from HT/Cluster triggers: Board Sums (pions/etas) Jet Patches

Acceptance of FMS

2011: 500 GeV Trans/Long Transverse Longitudinal

STAR Blue Beam AN As and alternative to Cross Ratio, the raw asymmetry can be plotted as a function of Cos() (with polarization axis at Phi=/2) Slope =AN Intercept = Luminosity Ratio for data set Luminosity ratio for all ~ - 0.31 ±.05 % Slope Fits are are consistent with Cross Ratio Method.  of 0 STAR  =0.07 AN=2.60±0.12 % Luminosity Ratio = -0.31 ±0.08 % AN=2.91±0.26 % Luminosity Ratio = -0.25 ±0.18 % AN=1.47±0.09 % Luminosity Ratio = -0.32 ±.06 %

Transverse Single Spin 0 Asymmetry vs PT for small and large 0 isolation cones. (Errors shown are statistical) STAR

Improvements for Run 12 Carl Gagliardi, Pibero Djawotho Overlapping Jet Patches Smoother acceptance for Board Sums for left/right rather than up/down L0 Trigger simulation online

Six Overlapping Jet Patches: DSM Reprogramming Add the encircled patches Skip the X’ed patches Six partially overlapping jet patches, each covering ~900 in azimuth Four existing quadrants, plus two sides (where |cos φ| is large) Give up top and bottom JPs (where |cos φ| is small) Cluster (aka: Board) sum triggers Only two thresholds for small cells (not a problem) Can maintain three thresholds in the large cells High tower triggers Give up for small cells during physics running

Optimization of Board Sum Acceptance In Run 11, small cell “cluster” (aka: “board”) sums were sums over sequential sets of four strips Indicated by red lines (e.g., A0-3, A2+3+B0+1, B0-3, …) Gave smooth acceptance across A-B-C (small |cos φ|) Board D sat by itself (large |cos φ|) Transverse spin measurements profit more from smooth acceptance at large |cos φ|, rather than small |cos φ|

Present Scheme Rotated inputs to boards B and C in each quadrant New B Boards A and D unchanged New C Rotated inputs to boards B and C in each quadrant Job for FMS group, not Trigger group Small cell “cluster” (aka: “board”) sums over sequential sets of four strips Put Board A by itself (small |cos φ|) Gives smooth acceptance across B-C-D (large |cos φ|) Simple change in small cell DSM Layer-0 algorithm

2012: 200 and 510 GeV Running 200 GeV 500 GeV + read out during Cu+Au running….

FMS Status: Data Participation Run 11 Transverse 500 GeV p-p ~20 /pb Longitudinal 500 GeV p-p ~2/pb Run 12 200 GeV p-p Transverse ~20 /pb 500 GeV p-p Longitudinal ~90 /pb Cu+Au ~2 weeks

Problems with FMS LED triggering problems Evidence for Graying of Lead Glass Lecroy HV Bad cards Observed strange excursions of voltage Possible origin of ‘gain jumps’ in large cells CW HV: Lost 1 week of running Bad device (1/2 of cells) 2 Bad cards ~40-100 large cells /36 small cells problems No FPD in Run 12 Problem with communication between FEQ and STP Need FPD*FMS

Need for LED Monitoring of PMT Gains ETA Yield NO LED corrections WITH LED corrections ETA

Evidence for Graying of Glass LARGE CELLS SMALL CELLS Blue = April 13 2012 Black= Mar 16 2012 Ratio of LgBs/SmBs increases by factor of 2 over 30 days ~15% increase in slope corresponds to -0.5% /day gain change for pp 500 Run 12

Evidence for Graying of Glass PION MASS LED DAY DAY Consistent with YuXi Pan’s estimate 0.2%/day for Run11 ~ 0.5 inst. Lum of Run 12

Evidence for Graying of Glass Run 11: 0.2%/day Run 12: 0.5%/day ~2x intensity Total graying ~ 25% for Run11/12 Conclusion: Leave it alone for Run 13 Unstack after Run 13 Repair large PMT bases Expose glass to sunlight to anneal f-centers

FMS Cell Status

FMS Repair Plans July-November Repairs: FPD communications UCLA:Stephen Trentalange, YuXi Pan PSU: Steve Heppelmann, Chris Dilks TAMU: Carl Gagliardi, Mriganka Mondal Repairs: LED setup, set number of RHIC clock tics Test of Lecroy HV stability Repair of CW mother board/ dead channels FPD communications

View of charged track in magnetic field For a charged particle exiting the constant field of a solenoid magnetic field through the a hole in a flux returning cap, about ½ of the angular bend in the constant field region is negated in the return region. sagitta

Forward Magnetic Tracking Summary A measurement of the charged track trajectory just inside the flux return (about 3 meters from the magnet center) can be projected to either the interaction vertex or to the FMS. The displacement between the projected track and measured track will be called .

View of charged track in magnetic field For a charged particle exiting the constant field of a solenoid magnetic field through the a hole in a flux returning cap, about ½ of the angular bend in the constant field region is negated in the return region. Region of PoleTip Carriage sagitta

Magnetic Field Mapping for FMS Extrapolation Method Extrapolate to FMS requires fringe field measurements to ~0.1(res)x0.5(fringe bend)B0sin(theta) =5%*B0sin(theta) ~25 Gauss Problem: Pole Tip Carriage ~10-100 Gauss disturbance

Conclusions FMS needs repair work over the summer Still capable of physics addressing pions, etas, jets, J/Psi? Extend to correlations with FPD, mid-rapidity in Run 13 Needed upgrades for different physics goals are the subject of this workshop Magnet mapping might be necessary for tracking in the forward region

LED Channel Map

Problems with FMS Loss of LED signal/power supply Loss of LED after power dips Combination of losses ~ several days Mostly effects large cell data (~10% of cells) Graying of Lead Glass Large cell HV problems Run11: ~12 channels for several days Run 12: ¼ of large cells lost HV for several days (controller) Small cell HV problems Helped to use onboard register to store HV value Loss of control to half of detector (Device 1) Loss of FPD Flakey communication between FEQ and STP Need FPD*FMS coincidence trigger